1. Field of the Invention
The present invention relates, in general, to an integrated system for extruding a polymer, drawn directly from a polymerization reactor, and formed into an end product.
2. Description of the Prior Art
In currently known processes for extruding synthetic polymer or resin sheets and film, pelleted resin produced by any one of several conventional polymerization processes and containing little or no dissolved monomer therein is heated to a molten state. The resin is then extruded through a die to provide a tube which is inflated from one end thereof by air introduced into the tube at the die orifice. Inflation of the tube, accompanied by stretching of the tube in an axial or longitudinal direction, biaxially orients the resin molecules so as to maximize the mechanical properties of the resulting film. The opposite or leading end of the inflated tube is then passed into the nip of a pair of cooperating rotatable rollers to provide a flat film. Although this process is widely employed in the manufacture of polyethylene, polypropylene and ethylene vinyl acetate films, as well as films of other thermoplastic resins, the process is subject to several drawbacks and limitations.
Thus, each of the operations required in the preparation of pelleted resin, i.e., extruding molten resin taken from a polymerization unit to form cylindrical strands, passing the strands through a cooling medium such as water to solidify the resin, cutting the solidified strands into segments of equal length to provide pellets, and thereafter drying the pellets, interposes additional energy-consuming steps in the manufacture of the final product.